1. Technical Field
The present disclosure relates to uninterruptible power supplies.
2. Description of Related Art
An uninterruptible power supply (UPS) is a backup power supply that is connected between a power source and an electronic device. The UPS provides power to the electronic device when the power source is down. Some UPS may be connected to a mains alternating current (AC) power source and to a solar powered power source. To save cost the UPS switches from the mains power source to the solar power source when the solar module is charged (by sunlight) to a minimum voltage. The UPS switches back to the mains power source when the solar module drops below the minimum voltage. The switching is done by an electromagnetic relay. If the electromagnetic relay is switching very frequently it is liable to be damaged. Therefore, there is room for improvement in the art.